Barre reduction process

ABSTRACT

A pre-dyeing method for substantially eliminating or at least greatlly reducing the potential for thermally induced barre in textured synthetic yarns or fabrics. In a preferred embodiment yarns or fabrics which are known or believed to be likely to develop thermal barre are heated briefly at a temperature essentially equal to the highest temperature reached by any portion of the yarn or group of yarns during texturing.

United States Patent [1 1 Quynn [451 Nov. 12, 1974 BARRE REDUCTIONPROCESS [75] Inventor: Richard G. Quynn, Greensboro,

[73] Assignee: Burlington Industries, Inc.,

Greensboro, N.C.

22 Filed: Dec.22, 1971 21 Appl. No.: 211,052

OTHER PUBLICATIONS H.U. Schmidlin. Preparation and Dyeing of SyntheticFibers, 1963. Publ. Chapman Hall Ltd. pp. 26-27. K. Venkataraman, TheChemistry of Synthetic Dyes. Vol. 2, I952, Publ. Academic Press lnc.,New York, pp. l350-5l.

Primary Examiner-Thomas J Herbert, J r. Attorney, Agent, orFirm-Cushman, Darby & Cushman [57] ABSTRACT A predyeing method forsubstantially eliminating or at least greatlly reducing the potentialfor thermally induced barre in textured synthetic yarns or fabrics. in apreferred embodiment yarns or fabrics which are known or believed to belikely to develop thermal barre are heated briefly at a temperatureessentially equal to the highest temperature reached by any portion ofthe yarn or group of yarns during texturing.

9 Claims, N0 Drawings BACKGROUND OF THE INVENTION This invention relatesbroadly to the texturing of synthetic fibers and yarns, and moreparticularly to a process for reducing or eliminating the fabric defectknown as barre, when this barre results primarily from thermalvariations during false-twist texturing.

The term barre," sometimes called barriness, and an anglicized versionof the French barre (stripe), has been broadly described in the art as aflaw in fabric consisting of textural or color bars in the direction ofthe warp or filling. In the context of this invention, the term isaccorded both a narrower and a broader connotation. It is narrower inthe sense that it relates only to barre of thermal origin. It is broaderbecause, whereas the word normally refers only to fabric, it is usedherein also to refer to yarns which if combined in fabrics will lead tothermal barre. Both meanings are perhaps better indicated by the wordsbarre potential." Whatever the context, barre ultimately refers hereinto the streakor band-like shade differences observed in dyed fabricsderived from textured yarns, where those yarns have been textured undernon-uniform thermal conditions.

It is thus herein more specifically called thermal barre," and it can beobserved clearly only after dyeing. Other forms of barre, derived, forinstance, from mechanical causes such as uneven knitting or weavingtensions, and sometimes visible even before dyeing, are not improved bythe process of this invention. Likewise the process does not reducebarre resulting from structural or geometrical differences.

In the past, once the potential for thermal barre had been introducedinto textured yarn, there appeared to be'only two general ways toelminate it: careful match ing of yarns by the weaver or knitter, andvariations in dyeing techniques, usually involving restrictions toparticular dyestuffs or costly process modifications. The latter methodoften produces deep shades and thus fails as a remedy when light shadesare desired. Even when reasonably effective, these methods have thefurther disadvantage that they offer no means for the texturer himselfto solve the barre problem arising from his processing. Rather, they aresolutions which can only be applied by his customers at a later stage.

Accordingly, the present invention is particularly concerned with barrearising from accidental or insufficiently controlled temperature and/orspeed fluctua tions during the runnning of false-twist or othertexturing mechines, or from combination in a fabric of yarns, fromdifferent twisting positions on false-twisting machine or from differentmachines, having sometimes subtly different thermal histories,sufficient to produce thermal barre.

Unless controlled in some way, barre leads to an excessive output ofseconds, i.e., fabrics which can be sold only at lower prices thanfirst-quality goods.

SUMMARY OF THE INVENTION This invention comprises a process forsubstantially eliminating or at least greatly reducing the potential forbarre and dyeing streaks induced in thermoplastic continuous filamentyarns during texturing, especially false-twist texturing, whenever thethermal history of the yarns is not uniform. The process comprisesapplying to a body of yarn or fabric a temperature and time of treatmentsufficient to eliminate or substantially reduce existent barrepotential, which temperature will preferably be near the highesttemperature experienced by any part of the yarn during texturing. Theinventiondepends upon the finding that thermal barre can be erased byequilibration of the thermal effects previously produced in theconstituent textured yarns in a barre-prone fabric.

Accordingly, an object of the present invention is to substantiallyeliminate thermal barre, as defined herein, from yarns and fabrics.

Another object is to provide a method for substantially reducingor'eliminating already present texturingproduced barre potential withouthaving to rely, as heretofore, wholly upon the skill of the knitter,weaver, and/or dyer.

DETAILED DESCRIPTION The process hereinafter described is directedtoward equilibrating the effects of unequal thermal histories oftextured yarns which otherwise would be barre-pronewhen combined infabric and dyed. The process of equilibration is a function of theconditions of temperature and heating time to which the material issubjected during application of the invention, which conditions arehereinafter more precisely defined.

More specifically, the invention consists of a process for substantiallyeliminating thermal barre potential in undyed barre-prone textilematerials made from textured synthetic yarns comprising dry heating thefabric, all of the yarn, or that portion of the yarn found by experimentto have been deficient in thermal input during texturing at atemperature and for a time sufficient to eliminate the thermal barrewhich otherwise, on dyeing, would result from the different thermalhistories of the yarns present.

Although primarily directed to barre, the invention is also applicableto the reduction or elimination of dyeing streaks in fabrics where saidstreaks owe their origin to the different thermal histories of theconstituent yarns during texturing. Such streaks may realistically beregarded as small-scale barre.

A barre-prone textile material, within the meaning of this invention, isa fabric, or a collection of fibers or yarns to be made into fabric,which fabric when dyed will produce thermal barre, as the latter isdefined hereinbefore. A collection of fibers or yarns may comprise onlya portionv of the yarns to be used in the fabric, whenever, as explainedherein, it is advantageous to subject only a portion of the yarn to theheat treatment of the invention.

If the material is already in fabric form, then the process must beapplied to at least that portion of the whole body of the fabric whichshows proneness to barre; if the material is still in yarn form, thenthe process may, if desired, be applied only to that part of the yarnwhich shows evidence of deficient thermal treatment during texturing,whether the latter be inclusive or exclusive of heat setting. Theprocess may be viewed as either a supplement to or a substitute forheat-setting of textured yarn or fabric, depending upon whetherheat-setting has or has not already been performed.

Although the process conditions are hereinafter best defined forpolyester yarns and fabrics, specifically those of polyethyleneterephthalate homopolymer or copolymer, it is believed that theinvention is also applicable to other thermoplastics, especially nylons,polypropylene, and cellulose triacetate, as well as to suita process foressentially equilibrating the'unequal effects of the varied thermalhistories of the component textured yarns and fibers in a barre-proneundyed fabric, said varied histories being the cause of thermal barre.

The nature and scope of the invention may be more clearly expressed,particularly in those instances where the extent of the variation of thethermal history of the component yarns is known or can be reasonablysurmised, as a process for heating all or at least the thermallydeficient portion of the yarn or fabric to a temperature preferably ator near the highest texturingv temperature/previously experienced by anypart of the textured yarn, usually in the range of about 190 to about230C, for a period of about 0.5 to 15 minutes, preferably about 1 to 5minutes. When the extent of the variation in thermal history is known,it may be expressed most simply as AT, the difference between the lowestand highest texturing temperatures; and the lower the value of AT, theshorter will be the time of additional heating required to overcome itsbarreproducing effect.

In the simplest case thermal barre exists between only two yarns, one ofwhich has been textured at a higher temperature than the other. Withnumbered letters being used to designate both yarns and their texturingtemperatures, if the two temperatures T, and T are known, where T ishigher than T the dry heat treatment of yarn T at temperature T willhave the effect of substantially reducing or eliminating barre betweenit and yarn T Less preferably, longer treatments at temperatures below Tare also effective. The duration of such heat treatment required toeliminate barre depends on the temperature differential AT, equaling T Theating times longer than minutes being specifically excluded from thescope of this invention. The time of treatment also varies with thedenier of the yarn, because of factors of heat transfer, as well as withthe chemical nature of the yarn, that is whether it be polyethyleneterephthalate, nylon 66, nylon 6, or another thermoplastic.

The dry heat treatment at temperature T of yarn T may be conductedseparately on yarn T but it is preferably performed after the two yarnsare combined in a fabric, and it may even be simultaneously orseparately performed on both yarns before knitting or weaving. So longas it is within the time limits of this invention, the heat treatmentappears to have essentially no effect on yarn T With filament polyester,the preferred yarn for this invention, prolonged dry heat treatment attemperatures below 230 C has, besides a barre-eliminating effect, onlythe general effect of reducing the overall depth of shade in subsequentdyeing.

The fact that barre potential may be eliminated by heating yarn T,equally well in either the presence or the absence of yarn T issurprising. It might logically be surmised that, since thermal barrearises from the existence of thermal variations during texturing, thethermal history effects of yarn T, could be equilibrated with those ofyarn T only by heating T, by itself. One could reasonably expect yarn Tto continue to change excessively if it were further heated along withyarn T The most important application of the process of this inventiondepends upon the surprising finding that barre potential is eliminatedby heating fabrics which contain bothyarns T and T were this not true,the invention could be applied only to yarns.

If more than two yarns are treated simultaneously, e.g., yarns T T and Twhere temperature T T T dry heat treatment at T of yarn T, will reducebarre between it and T but not necessarily betweenit and T within thetime limits of this invention. Treatment at I would reduce barre amongall three yarns.

In principle, in accordance with the teaching of this invention, allthermal barre among various yarns could probably be eliminated bytreatment forsufficiently long times at a temperature equal to thehighest temperature reached in texturing any one of the yarns. Inpractice the risk of damaging the tensile or other properties byprolonged heating limits the maximum time to about 15 minutes, and evenhere it is preferable when possible to avoid high temperatures, over sayabout 220 C with polyesters. Since polyester texturing is generallycarried out around 200 C, this latter restriction is not particularlysignificant. Neither is the time restriction a problem in practice, forthe magnitude of AT, while being sufficient to produce thermal barre, isusually unlikely to be greater than 5 to 10 C.

In actual practice in most instances where barre may arise, the valuesof temperatures T and T are not likely to be known. The temperaturerecords on the process are more likely to indicate that no difference(AT) had existed, since an individual texturers purpose would be toavoid temperature variations for reasons heretofore well known in theart. Should, however, the various machine positions be so monitored thata record is available on the temperature profiles of all the positions,or should the yarns being combined have come from different texturerswho had deliberately textured at different temperatures, recognition oftemperature T would of course be easier than here anticipated. All thatone most probably may know is that a number of different yarns, alltextured at the same nominal temperature but from different positionsand on different texturing machines, show barre when combined in fabricand dyed. The supposed temperature at which the texturing heaters areset is of course known, and one may know from experience to expect afluctuation of, for example, about i5 C in a particular position on themachine.

Under these latter conditions it becomes necessary to apply some simpleexperiments to small samples of barre-prone fabric to find the optimumconditions for subsequent treatment of the main body of the fabric, or,in other words, to discover the approximate value of T In theseexperiments samples are subjected to heat treatments within small unitsof temperature and time. When the optimum conditions for elimination ofbarre are found, the same conditions are applied to the large amount offabric to reduce its barre. Determination of these experimentalconditions, though more difficult than the simple application of a knownT temperature, is well within the ordinary skill of the art. Among thevariables to be considered are the total mass of yarn involved (totaldenier of yarn, or oz/yd of fabric), the geometrical structure of thefabric (single or double knit, woven, etc.), the means of carrying outthe heat treatments, whether by hot air, heated rolls or cans, etc., andthe degree of acceptability of barre mined experimentally for a givencombination of textured yarns, that optimum will be near the unknown Tfor that combination.

The ultimate causes of thermal barre, apart from the fact that itclearly arises from thermal variations during texturing, are obscure andimperfectly understood.

Since it is most probable that it is not the temperature of the heatsource that is controlling, but rather the temperature of the yarnitself, it is obvious that the time of exposure, i.e., the yarn speed,is a significant source of variation in the process, and thus of thermalbarre. A texturing machine position running at a higher or lower speedthan its fellows is as likely a place for thermal barre to arise as onerunning at a non-standard temperature.

Repeated tests of barre-prone combinations of yarns have shown that suchyarns very often cannot be distinguished from each other onthe basis ofdifferences in physical characteristics such as tensile strength,density, optical birefringence, or the like. While it is surmised thatthe differences which later appear in dyeing are of morphologicalorigin, depending upon relatively minor surface and/or internalstructural or crystalline differences induced by the texturing operationthat render the yarns incompatible with one another from the standpointof dye receptivity, it is recognized that these conclusions are onlyspeculative.

The invention solves the problem of finding a solution to thermal barreby making yarn dyeing characteristics uniform prior to full-scaledyeing, i.e., prior to commitment of the bulk of the yarn to dyeing.Once dyed, the fabric is essentially beyond stripping and redyeing;hence the ability to anticipate and prevent barre is of greatimportance.

The concept of this invention is closely related to the te ed, deas?!sedate .PE Q E temperature trol during texturing and heat setting, butit is applied even after the most careful control in texturizing hasfailed to prevent barre. It is perhaps also related to the known processof autoclaving, but besides the fact that it is applied at a highertemperature, for much shorter times, and for a different reason than thedimensional stabilization expected of autoclaving, it may alsoeffectively be used as a subsequent step after autoclaving.

The process is most advantageously applied to the output yarn fromsingle-heater texturing machines. When perfectly carried out in such amanner that barre-free yarn is produced, two-heater texturing by asingle texturer may eliminate the need to apply the invention. Applied,however, to those yarns or fabrics where two-heater texturing has failedto prevent thermal barre, the process of this invention effectssubstantial elimination of the barre. The invention thus goes beyond thestabilization role of the second heater, taking full account, as itdoes. of the importance of equalizing the effects of the entire thermalhistory of the constituent yarns in a fabric, said history being acombination of time, temperature, yarn speed, and efficiency ofheater-to-yarn heat transfer. The invention goes additionally beyondtwo-heater texturing in being applicable to fabrics.

The process of this invention is especially applicable to theelimination of barre from false-twist-textured yarns, but it is believedalso useful with yarns textured in other ways, such as stuffer-box,knife-edge, twist,

1 gear, jet, knit-deknit, and other methods of texturing, wherevariations in thermal history may be expected to arise.

Further process details and understanding of the invention are affordedby the following examples which r sailimit ivs- EXAM LEl Parent or feedyarns of DuPont Dacron Type 56 (polyethylene terephthalate homopolymer),150/34,

were textured at various nominal heater temperatures. This yarn,commonly used for texturing, a regular tenacity, semi-dull filamentyarn. Texturing was conducted on a single position of a Scragg Minibulktexturing machine equipped with a single 25 inch long heater, with yarnspeed 235 ft/min, false-twist spindle speed 200,000 rpm, :1 percentoverfeed, and theoretical (maximum) twist level about 70 tpi. Texturedyarns were prepared at texturing temperatures of 170, 190, 200, 210, 220and 230C, and not subsequently autoclaved. The yarns were then knittedsequentially into a sock or sleeve of about 2 inches diameter, eachtexturing temperature comprising about 1 /2 inches length of sleeve,with a small Lawson circular knitting machine. The sock was cutlengthwise into a number of strips, and these strips were then treatedfor 1 minute at temperatures of (one strip each) 170, 190, 200,

210, 220, and 230 C, free to shrink, in a laboratory, circulating-airoven. The six treated strips together with an untreated (control) stripwere then dyed together (in the same bath) according to a method knownfrom previous experience to emphasize barre effects: 1 percent (owf)Latyl Blue BCN, a DuPont blue disperse dyestuff, with Sg/liter of TypeM-l (biphenyl) carrier, at 210 F for 10 minutes at atmospheric pressure.The visual barre effects in the dyed, untreated (control) strip were:

170 vs. 190 C: marked barre 190 vs. 200 C: very slight barre; 190slightly deeper in shade 200 vs. 210 C: no detectable barre 210 vs. 220C: noticeable barre 220 vs. 230 C: very marked barre 1 In spite ofdifficulty in judging because of the narrow strip widths and theoccasional blotchy dyeing, the following observations were made on theheat-treated strips:

1. 1n the 2l0 C treated strip, the originally marked barre between and Cwas almost eliminated, but that between 220 and 230 remained.

4. In every case, hot-air treatment had the effect of l reducing orleaving unchanged the barre, and

n= insr 'a. inaiL- Results are herein presented in terms of visualimpressions of barre, rather than in reflectance or colonmetricmeasurements because it is the visual barre which is objectionable andin need of reduction.

scribed, each sock being dyed separately under the same conditions.Efforts were made to ensure uniformg ity of dyeing by good sampleagitation. The results of visual judgement of the degree of barre arecollected in 5 Table l. The rankings were made with a cardboard maskwhich blocked out all but the pair under consideration, since it wasnoticed that the eye is influenced by the sight of the other pairs.

EXAMPLE 2 A larger supply of textured yarns was prepared from the sameparent yarn and under the same texturin conditions as described inExample I. This time the various textured, unautoclaved yarns wereknitted sequentially into socks, and one entire sock each heattreatedfree to shrink for one minute at the various temperatures. Dyeing wasconducted as previously dewono l l l l l msofrosm am moangompwv; Son. 22

pee 3 3 2 e2 2 3 2 @3 2 E i $8 3 2 omm I am /I 08H m so 3262 303 33 5323 fififi m z 1533 3 3 2 e fi z 3%: U E: com I o8 I I finfi fi e fifi pw fifi fi SS BB fi fi fi e 233 33 M333 p z p E p z p z z bz 3w I 8m onmpompou o nmpompoul oanwpompou o ngoopow o pwpoopou afififi m I 82 $2 pz 32 $2 3 3 2 com I 8H a o: onpqoo 59G 83.5 @203 woosumn 0 28 um hm 32 325 6 m p w wfi pm w w m fip fip z v 9.03 I 00 am I homo D08 D08 B3 9.053 3 3 pm t s I. a 5m .QHE n .Hom mopmmaa pmmm ham uopmompco I mn mm chowH Emu;

The results of Table l are clearly consistent with those of Example 1,and illustrate (dotted lines of Table 1) that in order to eliminate orreduce, as far as possible, barre between any given pair, one shouldpreferably dry-heat-treat the pair at a temperature corresponding to thehigher characteristic temperature of the pair. Table 1 shows in severalplaces that treatment at a temperature which is somewhat lower than thisopeimum has the effect of reducing, but not eliminating, the barre. 1fthe treatment is conducted at a temperature substantially higher thanthat necessary for a given pair, one runs the risk of increasing thebarre be tween lower-temperature pairs (although not increasing itbeyond that of unheat-treated pairs). Thus, treatment of the 170/ 190 Cpair at 220 C, for example,

results in barre which is worse than that resulting from either 170 C or190 C treatment, but still better than that in the unheat-treated pair.

However, this risk is quite small in the majority of practical cases.The AT of C or C being dis"- cussed is very large by practicalproduction standards and it would be much more likely to have a knittedor woven fabric containing yarns which had been subjected duringtexturing to a temperature range of perhaps 5C or les sl l'fiti'sriwenrdee mostunusuar to'have' a fabric containing, for example, amajority of yarns textured at 200 C, a few yarns textured at 170 C, anda few more textured at 230 C.

EXAMPLE 3 This example illustrates the effects of a very high treatmenttemperature, one approaching the melting point of the fiber (about 258C, in the case of polyethylene terephthalate). Two sequentially-knittedsocks of the type described in Example 2 were hot-air treated at 250 Cfor 1 minute and 5 minutes. As expected, severe shrinkage of the yarnsoccurred, but the barre (after dyeing) was eliminated for all pairs, asfar as could be judged visually.

EXAMPLE 4 This example illustrates the effects of prolonged dryheat-treatment times. Socks of the type described in Example 2 weredry-heat-treated at 200 C for 2, 5, and 15 minutes. The 2-minutetreatment had the same effect (as far as could be judged visually) as inExample 2, i.e., elimination of the 200/ 190 C barre. The 5- minutetreatment additionally reduced the originally very marked 190/l70 barre,and the 15-minute treatment additionally reduced very much theoriginally marked 220/210 barre (the'original 210/200 barre not beingdetectable in any case). This last result, involving a treatment timemuch longer than would be necessary in most practical cases, indicatedthat dryheat treatment for prolonged times at a given temperature couldreduce barre between texturing temperature pairs higher than thetreatment temperature.

EXAMPLE 5 skeinfqrm s appose to th ab afo m of hsnthsL 10 examples. Theresults were more difficult to judge be cause of knitting difficultiesstemming from tangling of the yarn, but were similar to previousexperience at 200 C for 15 minutes (Example 4) except that the 220/210barre removal was not observed.

EXAMPLE 6 the two-heater type, i.e., one in which a second heater isplaced after the false-twist spindle, so that the yarn passessuccessively over a primary heater, through the false-twist spindle, andthen over a secondary heater before being wound onto a takeup package.

In this case the parent or feed polyester yarn, of the same type as inExample 1, was textured on a single position of an ARCT FT Fdouble-heater machine, at a yarn speed of 235 ft/min, spindle speed of186,500 rpm, +1 percent overfeed, for a theoretical (maximum) twistlevel of about 60 tpi. This machine had two heaters, each 22 in. long.The primary/secondary temperatures were 180/ 170, 210/200, and 240/230C. The lbarre shown by knitted and dyed socks containing un- ;treatedyarns was similar to that which resulted from a single heater at thesame corresponding primary temperature, i.e., similar to that of thecontrol sock of EX- :AMPLES l and 2. Dry-heat-treating, conducted as inEXAMPLE 7 This example demonstrates the application of the invention toa'barre-prone fabric where the texturing temperatures of the componentyarns were unknown. Experimental textured yarns were requested where itwas specified only that they be textured within the normal heater rangeof l220 C, that the difference not be greater than 10 C, and that thetexturing temperatures be withheld. The feed yarn was DuPont Type 56,/34 polyester yarn, textured on one position of a Leesona 555 machineequipped with single heaters 40 inches long. The yarn speed was 346ft/min, falsetwist spindle speed 270,000 rpm, +2 percent overfeed, for atheoretical (maximum) twist level of about 65 tpi. The unautoclavedyarns produced at the two unrevealed temperatures were then knitted intoeight identical socks, as in previous examples, in the followingsequence: about 1 1% inches sock length of yarn A, as inch of yarn B, 1k inches of yarn A. Thus a small portion of yarn B was placed with thelarger portions of yarn A on either side. After one of the socks wasdyed according to the barre procedure of Example 1, the narrow strip ofyarn B was distinguishable from the adjoining area in having a slightlydeeper (blue) shade; i.e., it exhibited barre with respect to itsneighbors. The other seven socks were separately heated in thecirculating air oven for 1 minute at 5 C intervals from C to 220 C, andthen dyed as before. Barre was clearly evident at all temperaturesexcept 205C and 210 C, being still faintly visible at 205 C. it wasjudged from the results that 210 C was the optimum temperature fortreatment. it was subsequently learned that yarn A hadbss ltex yrssl207? 9.3m! ram .1 t 2 C If the material is already in fabric form havingbeen woven or knitted from the previously made and textured syntheticyarn, a testing process similar to those previously described is used todetermine the optimum treatment temperature and additionally utilizeswellknown sampling techniques to determine portions of the fabric thatcontain yarns representative of the yarn from various sources used inthe fabric which yarns may have had non-uniform thermal histories. Allfabric swatches removed from these previously determined portions arethen individually tested in a manner similar to that used with respectto the knitted socks in the above examples to determine the optimumtreatment temperature and time for each of the swatches and in additionthe entire piece of fabric. Thereafter the fabric is heated at theoptimum temperature and for a time period as indicated by the abovetests. It is understood that many test variations either in samplingtechniques, swatch testing or methods of comparing treated and untreatedsamples can be used without departing from the scope of this invention.

It must be emphasized that an essential element of the invention is thatthe elimination or reduction of texturing-induced barre requires notsimply an unspecified heat treatment of the textured yarn, but atreatment the conditions of which (particularly temperature) arecorrelated with the previous texturing conditions. If the conditions ofthis barre eliminating treatment are chosen without regard to theprevious texturing conditions, the resulting barre may be made worserather than better. Table I of Example 2 shows an example where dry-heattreating at four temperatures caused increases of barre over that of the220lgg0igcontrol.

Although the present invention is described herein with particularreference to specific details, it is not intended that such detailsshall be regarded as limitations u on the scope of the invention exceptinsofar as inthetic yarns which have different dyeing characteristicscaused by thermal variation in the texturin of the yarns, said processcomprising dry heating said yarns, after texturing by a process from thegroup consisting of falssrtwist.astufisebqxzlaite-s5% t gear, jet,

and knit-deknit and before dyeing, at a temperature about equal to thehighest temperature used in texturing the yarns, said dry heating beingcontinued for a time period of from about 0.5 minutes to about 15minutes until the effects of thermal variation in texturing have beenequilibrated and only thereafter dyeing said yarns.

2. A process according to claim 1 wherein the textured synthetic yarnsare continuous filament thermoplastics.

3. A process according to claim 1 wherein said yarns are polyesteryarns.

4. A process according to claim 1 wherein said yarns are nylon yarns.

5. A process according to claim 1 comprising the steps of determiningportions of said fabric which contain yarns that are representative ofthe yarns used in the production of said fabric; removing at least onefabl'lC sample from at least one of said representative por-.

tions; dyeing at least a Eortion of each of said fabric samples toemphasize t e barre effect occurring between said yarns in each fabricsample; dividing said undyed Eortion of each of said fabric sample intostrips and dry eat treating each of said strips for constant periods oftime and at different temperatures; dyeing said strips in a mannersimilar to the way in which the previously dyed portion was dyed;comparing the previously dyed portion of each fabric sample with saidstrips divided out of the previously undyed portion of the same fabricsample after said strips have been heat treated and dyed; determiningthe amount of heat input, as a function of time and temperature,required to eliminate any barre effect existing between said yarns dueto thermal variation in previous texturing of said yarns; treating saidtextile material at said determined amount of heat input so that theeffects of said thermal variation are equilibrated in substantially allyarns within said textile material and dyeing said textile material.

6. A process according to claim 5 wherein said differnt temperatures arewithin the range of to 250 7. A process according to claim 5 whereinsaid different temperatures are within the range of to 230 UNITED STATESPATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3-,8h7,5 l 4 DatedNovember 12, 197

Inventor(s) Richard G. Quynn It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

l'l'HE SZECIFICATION:

Column 1, line 35, delete "elminate" and insert in lieu thereof--eliminate--.

Column 1, line 50, delete "meehines" and insert in lieu thereof--machines--.

Column t, line 11, delete "I and insert in lieu thereof Signed andsealed this 27th day of May 1975.

(SEAL) Attest:

C MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officerand Trademarks FORM POJOSO (IO-69)

1. A PROCESS FOR SUBSTANTIALLY REDUCING OR ELIMINATING THERMAL BARRE INA DYED FABRIC COMPRISING TEXTURED SYNTHETIC YARNS WHICH HAVE DIFFERENTDYEING CHARACTERISTICS CAUSED BY THERMAL VARIATION IN THE TEXTURING OFTHE YARNS, SAID PROCESS COMPRISING DRY HEATING SAID YARNS, AFTERTEXTURING BY A PROCESS FROM THE GROUP CONSISTING OF FALSE-TWIST,STUFFER-BOX, KNIFE-EDGE, TWIST, GEAR, JET AMD KNIT-DEKNIT AND BEFOREDYEING, AT A TEMPERATURE ABOUT EQUAL TO THE HIGHEST TEMPERATURE USED INTEXTURING THE YARNS, SAID DRY HEATING BEING CONTINUED FOR A TIME PERIODOF FROM ABOUT 0.5 MINUTES TO ABOUT 15 MINUTES UNTIL THE EFFECTS OFTHERMAL VARIATION IN TEXTURING HAVE BEEN EQUILIBRATED AND ONLYTHEREAFTER DYEING SAID YARNS.
 2. A process according to claim 1 whereinthe textured synthetic yarns are continuous filament thermoplastics. 3.A process according to claim 1 wherein said yarns are polyester yarns.4. A process according to claim 1 wherein said yarns are nylon yarns. 5.A process according to claim 1 comprising the steps of determiningportions of said fabric which contain yarns that are representative ofthe yarns used in the production of said fabric; removing at least onefabric sample from at least one of said representative portions; dyeingat least a portion of each of said fabric samples to emphasize the barreeffect occurring between said yarns in each fabric sample; dividing saidundyed portion of each of said fabric sample into strips and dry heattreating each of said strips for constant periods of time and atdifferent temperatures; dyeing said strips in a manner similar to theway in which the previously dyed portion was dyed; comparing thepreviously dyed portion of each fabric sample with said strips dividedout of the previously undyed portion of the same fabric sample aftersaid strips have been heat treated and dyed; determining the amount ofheat input, as a function of time and temperature, required to eliminateany barre effect existing between said yarns due to thermal variation inprevious texturing of said yarns; treating said textile material at saiddetermined amount of heat input so that the effects of said thermalvariation are equilibrated in substantially all yarns within saidtextile material and dyeing said textile material.
 6. A processaccording to claim 5 wherein said different temperatures are within therange of 170* to 250* C.
 7. A process according to claim 5 wherein saiddifferent temperatures are within the range of 190* to 230* C.
 8. Aprocess according to claim 7 wherein the heat treatment is a dry-heattreatment for a period of about 1 minute to about 5 minutes.
 9. Aprocess according to claim 5 whereiN said textured yarns contain acombination of at least two different fiber forming materials.